Apparatus for providing the coordinated rotation of two interrelated components

Abstract: An apparatus (10) for providing the coordinated rotation of two interrelated components (12, 14) includes first and second cam segment lobes (20, 22) each respectively associated with the interrelated components (12 14) , the cam segment lobes (20, 22) are urged into rotatable contact with each other such that when the components (12, 14) are subjected to a torque the lateral distance therebetween is changed.

Description: The present invention generally relates to an apparatus for providing the coordinated rotation of two interrelated components and, in particular, relates to one such apparatus having first and second cam segment lobes each respectively associated with first and second devices and including means for urging the first and second cam segment lobes into rotatable contact with each other. There are many instances where it is desirable to control the coordinated rotation of two interrelated components. One of the more common instances is the adjustment of the interocular distance between two eyepieces, such as the eyepieces used in microscopes, binoculars and other optical devices. Although the detailed description of this invention will be directed to an optical device embodiment, it will be apparent to those skilled in the mechanical arts that the present invention is not, in fact, so limited. Conventional interocular distance adjustment mechanisms include such arrangements as interocular gear systems and fork and pin drives. In general, gear systems are expensive and can be quite complex if little or no play is acceptable. Further, in such play-free arrangements the movement is usually ergonomically rough due, primarily, to the high frictional load placed on the bearings of such a system. Typical fork and pin drive mechanisms not only exhibit noticeable play but also a changing rate of interocular rotation along with excessive friction at the pin/fork interface. Although the interocular gear system and the pin and drive arrangements are acceptable in many applications they are frequently unacceptable in applications where precise, smooth, play-free adjustment of the interocular distance of two eyepieces is required. For example, there is an ever increasing use of microscopic instruments in the field of medical examination and surgery. In such circumstances, the use of interocular gear systems or fork and pin drives is, for the deficiencies cited above, quite unacceptable to the user. JP-A-61-116311, discloses a distance adjustment apparatus for changing the distance between two lens systems. There, each lens system is connected with an arm extending perpendicular to the optical axis. The two arms of both lens systems are rotatably connected to each other by means of an axis. Such a structure not only requires a complicated machining of the ends of the arms to be connected to the axis but also the provision of an axis and respective mounting steps for attaching the arms to the common axis. GB-A-622,466, has already been published in 1949, that is 44 years before the priority date of the present application. This reference discloses binoculars having two telescope lenses which are arranged to turn about two axis. Each telescope is provided with a plate which is rotatably connected to the respective axis, and has at their end a semi-circular shape provided with gear teeth. The gear teeth of the two plates are meshing with each other so as to provide a gear-like engagement. Hence, it is highly desirable to provide an interocular distance adjustment apparatus that is inexpensive, precise, play-free and comfortable to use. Accordingly, it is one object of the present invention to provide an apparatus for providing the coordinated rotation of two interrelated components that substantially overcomes the drawbacks of conventional systems. This object is accomplished by an apparatus according to claim 1. Other objects and advantages will become apparent to those skilled in the art from the following detailed description of the invention read in conjunction with the appended claims and the drawings attached hereto. The drawings, not drawn to scale, include; Figure 1 which is a perspective view of an interocular distance adjustment apparatus embodying the principles of the present invention; Figure 2 which is side view of the interocular distance adjustment apparatus shown in Figure 1; and Figure 3 which is a wall portion of a housing particularly useful in conjunction with the apparatus shown in Figure 1. An apparatus, generally indicated at 10 in the drawings and embodying the principles of the present invention, for providing the coordinated rotation of two interrelated components, 12 and 14 , respectively, includes first and second cam segments, 16 and 18 , respectively, each having a cam segment lobe, 20 and 22 , respectively, associated therewith, and means 24 for urging the cam segment lobes, 20 and 22 , into contact with each other such that when a torque is applied to either one or both of the components, 12 and 14 , the lateral distance between the components, 12 and 14 , is changed. In the embodiment shown, the apparatus 10 is an optical apparatus wherein the first and second components, 12 and 14 , respectively, are eyepieces. Each eyepiece includes a body 25 having a viewing end 26 and a light receiving end 28 . In such an embodiment, the eyepieces include a plurality of optical elements, not shown in the drawings, for directing light received at the light receiving end 28 to the viewing end 26 . Consequently, the light receiving end 28 has an optical axis 30 associated therewith and the viewing end 26 has an optical axis 32 associated therewith. Typically, as shown, the optical axis 30 of the light receiving end 28 of each component, 12 and 14 , is substantially parallel with and offset from the optical axis 32 of the viewing end 26 . In one particular embodiment, each of the components, 12 and 14 , includes a cylindrical shaft, 34 and 36 , respectively, extending from the body 25 at the light receiving end 28 thereof. In this embodiment, the shafts, 34 and 36 , extend through a wall 38 of a housing 40 . Preferably, one of the shafts, for example, shaft 34 , is fixedly mounted through a first opening 42 , as shown in Figure 3, in the wall 38 by means of a bearing 44 that allows only rotational movement of the shaft 34 . The other shaft 36 extends through an elongated opening 46 , as shown in Figure 3, through the wall 38 that allows both rotational movement of the shaft 36 as well as movement lateral with respect to the shaft 34 . Preferably, in such an embodiment, the eyepieces are secured to the housing 40 by securing the first and second cam segments, 16 and 18 , respectively, to the first and second shafts, 34 and 36 , respectively, on the side 48 of the wall 38 opposite the respective viewing ends 26 . In one preferred embodiment, each cam segment, 16 and 18 , includes a shaft opening 50 sized to receive therethrough one of the shafts, 34 or 36 . Each cam segment 16 and 18 , also includes one of the cam segment lobes, 20 and 22 , respectively. Typically, in the preferred embodiment, each cam segment lobe, 20 and 22 , defines an arc segment of a circle that is concentric with the shaft opening 50 of the respective cam segments, 16 and 18 . Preferably, each of the cam segment lobes, 20 and 22 , subtends between 20 degrees and 50 degrees of arc. In the embodiment shown, each cam segment, 16 and 18 , is provided with at least one slot 52 extending into the cam segment, 16 and 18 , from the periphery of the shaft opening 50 . Each shaft, 34 and 36 , is provided with keys 54 sized to extend into the corresponding slots 52 . The keys 54 and slots 52 are disposed such that when the cam segments, 16 and 18 , are fitted onto to shafts, 34 and 36 , respectively, the first and second cam segment lobes, 20 and 22 , respectively, face each other. Preferably, the keys 54 and slots 52 are disposed so that the point of contact of the cam segment lobes, 20 and 22 , lies along a line connecting the optical axes 30 of the light receiving ends 28 of the components, 12 and 14 . The cam segments, 16 and 18 , can be secured to the cylindrical shafts, 34 and 36 , respectively, by any means known in the art, including frictional fitting, epoxying, or the like. Preferably, each cam segment, 16 and 18 , includes a peripheral groove 56 that is concentric with the shaft opening 50 such that a substantial amount of each cam segment lobe, 20 and 22 , is grooved. The periphery 58 of each cam segment, 16 and 18 , is machined to provide an anchor pin 60 . Preferably, the anchor pins 60 are formed distal each other. In the preferred embodiment, the means 24 for urging the cam segment lobes, 20 and 22 , into contact with each other includes a preloaded spring wire that is wrapped around the cam segments, 16 and 18 , in the grooves 56 thereof. It has been found that one and a half figure eight windings work quite effectively although other winding configurations can also be implemented. In such embodiment, the spring wire is wrapped around the anchor pins 60 to secure the wire in place and to maintain the tension thereon. In order to further ensure that the wire maintains a constant tension, epoxy 64 can be applied to the distal portions 62 of the cam segments, 16 and 18 , subsequent to the winding and anchoring of the wire. In one particular embodiment, the grooves 56 are about 711 µm (0.028 inches) wide and the spring wire is 203 µm (0.008 inches) in diameter. The diameter of the first opening 42 , the width of the elongated opening 46 and the outside diameter of the cylindrical shafts, 34 and 36 , are cooperatively sized so that the cylindrical shaft 36 moves smoothly in a lateral direction within the elongated opening 46 . The spring wire is wound about the shafts, 34 and 36 , to a tightness that allows both smooth movement and play-free adjustment. Hence, it will be understood that the apparatus 10 provides smooth, play-free and relatively inexpensive coordinated rotation between the components, 12 and 14 .

Claims: Apparatus for adjusting a distance between first and second optical components (12, 14) characterised in that it comprises: first and second cam segments (16,18) connected to said first and second components (12,14), respectively and having first and second cam segment lobes (20,22); and urging means (24) connected to said cam segment lobes (20,22), for urging said first and second cam segment lobes into contact with each other, such that the lateral distance between the optical components is adjusted when a torque is applied to either component. The apparatus of claim 1 wherein a spring wire member (24) is disposed around said first and second cam segment lobes (20,22). The apparatus of claim 2 wherein each cam segment lobe (20,22) includes a groove (56), said spring wire member (24) being disposed into said grooves. The apparatus of claim 1, 2 or 3 characterized in that it is an adjustable eyepiece. The apparatus according to claim 1, 2, 3 or 4 further comprising a housing member (40) having a first and second opening (42,46); means (44) for rotatably securing said first optical component (12) in said first opening; and means (46) for slidably securing said second component (14) in said second opening. The apparatus as claimed in claim 3 wherein each said first and second peripheral groove (56) extends substantially completely through said first and second cam segment lobe (20,20) respectively. The apparatus of anyone of claims 2 to 6 wherein said spring wire member (24) is wrapped around said cam segments (16, 18) in said grooves (56) . The apparatus as claimed in claim 7, wherein said spring wire member (24) is wrapped around said cam segments in a figure-eight. The apparatus as claimed in claim 8 wherein said spring wire member (24) includes one and a half figure-eight turns. The apparatus as claimed in anyone of the preceding claims wherein each said cam segment (16,18) includes an anchor pin (60) at the periphery thereof and the ends of said spring wire member (24) are secured to said anchor pins. The apparatus as claimed in anyone of claims 3 to 10 wherein said spring wire member (24) is epoxied into said groove of each said cam segment. The apparatus as claimed in anyone of the preceding claims wherein each said cam segment lobe (20, 22) subtends an arc of between about 20 degrees and 50 degrees.

Inventors: DEVENYI GABOR, DEVENYI, GABOR
Applicants: HUGHES AIRCRAFT CO, HUGHES AIRCRAFT COMPANY
Application year: 1994
Main classification: G02B7
IPC codes: G02B7, F16C11, G02B23